The present invention relates to improved high-voltage switchgear, and more specifically, to metal-enclosed, two-way transfer switchgear which includes high-voltage switches, operating mechanisms for the switches, and high-voltage fuses, all in a metallic enclosure. The type of switchgear contemplated by the present invention includes one three-phase switch connectable to a preferred source of high-voltage electricity and another three-phase switch connectable to an alternate source of high-voltage electricity. Electrical power is supplied to electrical loads through high-voltage fuses connectable to the switches. Normally, the preferred source energizes the loads; should anything untoward occur with or in the preferred source, the switch associated therewith is opened and the switch associated with the alternate source is closed to disconnect the preferred source from the loads and to connect the alternate source to the loads through the fuses.
Various types of high-voltage switchgear which include stored-energy operating mechanisms for the switches thereof are well known, as exemplified by numerous, commonly-assigned U.S. Patents and Patent Applications set forth below. The present invention relates to improvements in such high-voltage switchgear. Specifically, according to various aspects of the present invention, the operating mechanisms for the switches may have mechanical energy stored therein either automatically, by a motor, or manually, by manipulation of a hand crank. The energy, once stored, may be either automatically released, in response to the condition of the preferred and alternate sources, or may be manually released, regardless of the condition of the sources at the option of operating personnel, to affect the condition of the switches. Each operating mechanism may be decoupled from its switch so that they may be exercised for maintenance or adjustment purposes without affecting the condition of the switches. The manual release of the energy stored in the operating mechanisms is prevented when energy is in the process of being stored therein by either the motor or the hand crank. Also, engagement of the hand crank with either operating mechanism preparatory to manually storing mechanical energy therein prevents its motor from attempting to store energy therein and also prevents automatic or manual release of any energy stored within the operating mechanism. Decoupling of the operating mechanisms from their switches causes the switches to be locked in their extant position at the time of decoupling and may also prevent automatic operation of the switchgear while such uncoupled condition exists, although manual operation may occur.
The improved switchgear also includes appropriate legends visible to operating personnel and informing whether mechanical energy is or is not stored within each operating mechanism, whether each operating mechanism is in the switch-closed or the switch-open position, whether or not each switch is closed or opened, and in what direction the hand crank must be rotated in order to manually store mechanical energy in each operating mechanism.
The above and other features of the present invention all serve to render the switchgear thereof improved from the standpoints of convenience of use, reliability and the safety of operating personnel. The present invention represents an improvement over various commonly-assigned U.S. Patents and Patent Applications, all cited hereinafter.